Cortisol is produced in the adrenal glands and released into the blood stream of the body in response to stress. While everyone copes with stress differently, any high level of stress and overproduction of cortisol can lead to dangerous side effects including high blood pressure, severe fatigue, severe anxiety, and even depression. Excess production of cortisol is also linked to stress disorders, such as insomnia, Cushing's syndrome, and Post Traumatic Stress Disorder (PTSD). Depending on a person's pattern of activity, cortisol production may differ throughout the day. Typically, an individual who wakes up in the morning to work has the highest production of cortisol in the morning and lowest at night; this trend reverses if the individual has more rest in the morning and works late at night. Hence, continuous monitoring and point of care (POC) testing is the most optimal way to get the most accurate results for different patients.
As it stands now, patients must go out of their way and provide a sample to a clinic or laboratory. In addition, patients must wait a long time for samples to get processed and to receive result. This is detrimental because production levels of cortisol differ for each individual and sex throughout the day, meaning there can be inaccuracies in the results. POC testing is therefore important for personalized diagnosis and treatment.
Currently, a cortisol level from a sample can be detected using immunoassay chromatography, like enzyme-linked immunosorbent assay (ELISA). An electrochemical technique, cyclic voltammetry, is also used for characterization of cortisol in a sample. The systems used in these laboratories to detect the concentration of cortisol are bulky, expensive, time consuming, and require training to operate. As a result, patients don't have access to real-time, continuous monitoring or POC testing for cortisol. Similar problems exist in testing for many other analytes.